1G 2.3L 6 Bolt DSM Eagle Forged 100mm Stroker Crank Crankshaft, Any Issues, Problems?

[Car Cannibal]

I wanna go 6 bolt, 2.3L, 100mm Eagle forged crank but I'm getting some rough stories from mechanics and some builders about them. Seems like the thrust can be an issue if you start pushing them, they had examples of drag strip stories vs stock crank at the same power level. Stock wins.

I'm 99% street and looking for 650-700hp, but issues are not worth it IMO, but I can't seem to find anything about issues with Eagle stroker crank's. The street torque gain is my main reason for going that route, not looking to Rev to 8500rpm or 3rd gear WOT on the street really.

Anyone with these cranks care to post good or bad?

Thanks

 

[We're on Boost]

I had to look into this when my engine was planned. I was planning a 94mm crank though, rather than the 100mm. We planned Eagle, because the more expensive and probably better K1 crank was not available for the 6-bolt.
My plan was and still is most or all street, probably no race. Long life. And a "safe" rev limit, which we decided 8,000 to be super safe. Haha

My invoice from English Racing shows the crank like this:
"English Racing spec 94mm Eagle crank. Mods to make it better".

I don't know what they did to "make it better".
But I did make note of some comments by engine builders in EvoM about the stroker Eagle cranks.
Follow this link to EvoM. This is Search results within a stroker thread, searching for the keyword "Eagle".

https://www.evolutionm.net/forums/search.php?searchid=26907907

I get 11 results on this search. It's a very long thread.

I would say, start out with post #331 by "JohnBradley" who is Aaron at English Racing.
He is their main tuner. Not actually their engine builder. But he knows what he's talking about.

https://www.evolutionm.net/forums/e...2-2-3-2-4-motors-strokers-23.html#post8964404

Also look at posts #316, 317, and 336. There are also older posts in that thread I haven't looked at and don't know what's there.

 

[llxkevinxll]

If you haven't seen this. Worth a look.

 

[bastarddsm]

fwiw my brother has a 7 bolt 2.3 in his fairmont with a stock 100mm crank. it has 6 bolt rods with ARP bolt that we narrowed to use on a 7 bolt crank. It goes 8500 ALLL THE TIME. It's got a vortech supercharger on it, so the 400~ it makes at the crank is probably closer to 450 in a turbo motor.... I don't think it would be an issue turning it 9000.

As for the eagle crank, I've been told that they are not always straight, and it could be an issue just slamming a motor together not paying attention to that. This isn't just an eagle issue, all cranks can be bent, there can be a lot of residual stress in them from the forging process, or grinding, or even polishing them. they are usually straightened pretty easy.

Lastly there is some funny math in that stroke or not paper. Mostly it is pretty good guidlines, but I wouldn't use it as a guide to engineer a combination to the max or anything.

Lastly again, if you are using a mitsu manual trans, avoid the stroker you can go faster with a 2.0 and not break as much. Dogbox I feel like do the stroker as the closer gears help keep shift point down, and the tall first can use the extra torque.

 

[llxkevinxll]

fwiw my brother has a 7 bolt 2.3 in his fairmont with a stock 100mm crank. it has 6 bolt rods with ARP bolt that we narrowed to use on a 7 bolt crank. It goes 8500 ALLL THE TIME. It's got a vortech supercharger on it, so the 400~ it makes at the crank is probably closer to 450 in a turbo motor.... I don't think it would be an issue turning it 9000.

Any comments on motor long term longevity? I feel like I see comments, including in that PDF, about more side loading due to rod ratio or whatever causing issues long term.

Edit: To clarify "long term" I mean are we talking 5k miles issue free? Maybe something pops up after 30k or something depending on how much time it spends in the high revs? I do not mean factory service life.

 

[bastarddsm]

We have had it apart a couple times to check stuff over, and have not really saw any issues. 50% of it's life has been say 6000rpm+ It's a mutt, and is using cheap ebay honda k20 pistons with mini skirts.. and it's about 10.5:1. it's only got a few hundred miles on it, but like I said most of that is 1/4mi at a time. We have made 25hits in a day when doing development work on the supercharger. I would have have no worries about longetivity with a well built 2.3 at the 500hp range for general street/drag abuse. road race or other severe use, idk.

From my experience piston material choice will have more of an effect on life than the stroke in a mildish street application - say 500whp or less. More than that and I think cylinder wall failure becomes a real issue, and piston skirt choice along with maximizing wall thickness becomes important. I've never run a 2.3 at that kinda power level so my experience is limited. I have had a 0.040" over 2.0 bust a cylinder wall and I can directly attribute that to piston skirt design primary, and cylinder wall thickness/fatigue secondary. That was in the 7-800hp area depending on whose dyno ect..

 

[EC17PSE]

If i remember correctly the eagle cranks used to come in very un bakanced and always needed extra work to be made correct! But once done they can be good and many have used them for high revs and high hp cars. How long i dont know as at some point everyones broken at least 1 cranks from most brands whether it be billet or forged.

Also you have to remember the lower the rod ratio the worse off you are and on a higher leverage crank like 100mm its very low so your putting massive amounts of stress on everything from piston bores, pistons, rods and crank!

For your power lever your torque will kill your trans all the time! Nothing around it! Even a ppg will eventually fail on it mostly due to the size of the gears and teeth in the box. You will find more problems for you're self and costly ones at that going this route.

A 2.1 destroker can handle torque and revs so would be safer.

I would rsther build the torque from the turbo and tuning vs internals as when your up in the rpm its alot safer generally for torque vs low end where it can strip things way to easy